// calc tangent at x=a
@Override
public final void compute() {
double a = n.getDouble();
if (!f.isDefined() || !deriv.isDefined() || Double.isInfinite(a) || Double.isNaN(a)) {
tangent.setUndefined();
return;
}
// calc the tangent;
double fa = f.evaluate(a);
double slope = deriv.evaluate(a);
tangent.setCoords(-slope, 1.0, a * slope - fa);
T.setCoords(a, fa, 1.0);
}
@Override
public void compute() {
int degInt;
GeoList coefs = null;
fv.setVarString(f.getVarString(StringTemplate.defaultTemplate));
// px^2+qx+r; p+q+r=s;
double r = f.evaluate(0);
double s = f.evaluate(1);
double p = 0.5 * (s + f.evaluate(-1)) - r;
double q = s - p - r;
boolean isQuadratic = !f.isGeoFunctionConditional();
double[] checkpoints = {1000, -1000, Math.PI, Math.E};
for (int i = 0; i < checkpoints.length; i++) {
double x = checkpoints[i];
if (!Kernel.isZero(p * x * x + q * x + r - f.evaluate(x))) {
// App.debug(p + "," + q + "," + r + ","
// + (p * x * x + q * x + r - f.evaluate(x)));
isQuadratic = false;
}
}
if (!isQuadratic) {
if (algoCoef == null) {
algoCoef = new AlgoCoefficients(cons, f);
algoCoef.setProtectedInput(true);
algoCoef.remove();
} else {
algoCoef.compute();
}
coefs = algoCoef.getResult();
degInt = coefs.size() - 1;
isQuadratic = coefs.isDefined() && coefs.get(0).isDefined();
for (int i = 1; i < degInt; i++) {
if (2 * i != degInt && !Kernel.isZero(((GeoNumeric) coefs.get(i)).getDouble())) {
isQuadratic = false;
}
p = ((GeoNumeric) coefs.get(0)).getDouble();
q = ((GeoNumeric) coefs.get(degInt / 2)).getDouble();
r = ((GeoNumeric) coefs.get(degInt)).getDouble();
}
} else {
degInt = 2;
}
if (degInt % 2 == 1 || degInt < 2 || !isQuadratic || Kernel.isZero(p)) {
square.setUndefined();
return;
}
if (lastDeg != degInt) {
ExpressionNode squareE;
ExpressionValue fvPower;
if (degInt == 2) fvPower = fv;
else
fvPower = new ExpressionNode(kernel, fv, Operation.POWER, new MyDouble(kernel, degInt / 2));
squareE =
new ExpressionNode(
kernel,
new ExpressionNode(
kernel,
a,
Operation.MULTIPLY,
new ExpressionNode(kernel, fvPower, Operation.MINUS, h)
.power(new MyDouble(kernel, 2))),
Operation.PLUS,
k);
square.getFunction().setExpression(squareE);
}
lastDeg = degInt;
fv.setVarString(f.getVarString(StringTemplate.defaultTemplate));
// if one is undefined, others are as well
square.setDefined(!Double.isNaN(r));
a.set(p);
h.set(-q / (2 * p));
k.set(r - q * q / (p * 4));
}